Controlling a gas turbine considering a sensor failure

Abstract

A system for controlling a gas turbine, includes a control system for providing control signals to a gas turbine; a tuning system for providing tuning signals, a modelling system for generating virtual measurement signals, the virtual measurement signals being based on the control signals and the tuning signals; a sensor diagnostics system for diagnosing at least one sensor measurement signal and outputting control system reconfiguration signals to the control system and tuner system reconfiguration signals to the tuning system, the tuning signals being based at least on the tuner system reconfiguration signals, the control signals being based on the at least one sensor measurement signal, the virtual measurement signals and the control system reconfiguration signals.

The invention claimed is: 
     
       1. A system for controlling a gas turbine, comprising:
 a control system configured for providing control signals to the gas turbine; 
 a tuning system configured for providing tuning signals, 
 a modelling system configured for generating virtual measurement signals, the virtual measurement signals being based on the control signals and the tuning signals; 
 a sensor diagnostics system having sensor diagnostic logic for diagnosing at least one sensor measurement signal and outputting control system reconfiguration signals to the control system and tuner system reconfiguration signals to the tuning system, 
 wherein the sensor diagnostics system is distinct from the control system, 
 wherein the control system reconfiguration signals are derived for improved reconfiguration of the control system, 
 wherein the tuning signals are based at least on the tuner system reconfiguration signals, wherein the control signals are based on the at least one sensor measurement signal, the virtual measurement signals, and the control system reconfiguration signals, 
 wherein the sensor diagnostic system is connected by way of a parallel connection to the control system and to the tuning system, 
 wherein the control system reconfiguration signals to the control system and the tuner system reconfiguration signals to the tuning system are supplied via the parallel connection to simultaneously reconfigure the control system and the tuning system based on the sensor diagnostic logic. 
 
     
     
       2. The system according to  claim 1 , further comprising: an estimator configured for estimating health parameters based on the at least one sensor measurement signal, wherein estimated health parameters are provided to the tuning system, wherein the tuning signals are further based on the estimated health parameters. 
     
     
       3. The system according to  claim 1 , wherein the modelling system is further configured to generate predicted health parameters which are provided to the tuning system, wherein the tuning signals are further based on the predicted health parameters. 
     
     
       4. The system according to  claim 1 , wherein the virtual measurement signals are also provided to the sensor diagnostic system, wherein the control system reconfiguration signals and the tuner system reconfiguration signals are further based on the virtual measurement signals. 
     
     
       5. The system according to  claim 1 , wherein the control system comprises:
 a first regulator; 
 a second regulator; 
 wherein control signals comprise first control signals and second control signals, wherein the first regulator is configured for generating the first control signals and wherein the second regulator is configured for generating the second control signals; 
 a control output switching system configured to output selectively the first control signals or the second control signals, wherein a state of the control output switching system is based on the control system reconfiguration signals. 
 
     
     
       6. The system according to  claim 5 , wherein the control system comprises:
 a sensor output switching system configured to selectively provide the at least one sensor measurement signal or the virtual measurement signals to the second regulator, 
 wherein a state of the sensor output switching system is based on the control system reconfiguration signals. 
 
     
     
       7. The system according to  claim 6 , wherein the sensor diagnostics system is configured to determine a sensor residual being a difference between the at least one sensor measurement signal and a corresponding virtual measurement signal among the virtual measurement signals. 
     
     
       8. The system according to  claim 7 , wherein the control system reconfiguration signals define a condition for switching the control output switching system based on the sensor residual and at least one threshold. 
     
     
       9. The system according to  claim 7 , wherein the control system reconfiguration signals define a condition for switching the sensor output switching system based on the sensor residual and at least one threshold. 
     
     
       10. The system according to  claim 7 , wherein the tuner system reconfiguration signals provided to the tuning system are used to respectively adjust a turbine state transition matrix and a filter gain matrix, based on the sensor residual, wherein respectively adjusted turbine state transition matrix and filter gain matrix define an evolution of operational states of the gas turbine. 
     
     
       11. The system according to  claim 10 , wherein the respectively adjusted turbine state transition matrix and filter gain matrix are defined as a product of: 1) a compensation matrix and 2) an initial turbine state transition matrix and filter gain matrix, the compensation matrix being diagonal and having elements differing from one (1) depending on a magnitude of a corresponding residual. 
     
     
       12. The system according to  claim 1 , wherein the at least one sensor measurement signal comprises a compressor discharge pressure measurement signal,
 wherein a rotation shaft power is controlled to be below a limit and/or compressor discharge pressure is limited according to a predetermined schedule. 
 
     
     
       13. A method for controlling a gas turbine, comprising:
 by a control system, providing control signals to the gas turbine; 
 by a tuning system, providing tuning signals, 
 by a modelling system, generating virtual measurement signals, the virtual measurement signals being based on the control signals and the tuning signals; 
 by a sensor diagnostics system having sensor diagnostic logic for diagnosing at least one sensor measurement signal, outputting control system reconfiguration signals to the control system and tuner system reconfiguration signals to the tuning system, 
 wherein the sensor diagnostics system is distinct from the control system, 
 wherein the control system reconfiguration signals are derived for improved reconfiguration of the control system, 
 wherein the tuning signals are based at least on the tuner system reconfiguration signals, wherein the control signals are based on the at least one sensor measurement signal, the virtual measurement signals, and the control system reconfiguration signals, 
 connecting the sensor diagnostic system by way of a parallel connection to the control system and to the tuning system, and 
 supplying via the parallel connection the control system reconfiguration signals to the control system and the tuner system reconfiguration signals to the tuning system to simultaneously reconfigure the control system and the tuning system based on the sensor diagnostic logic. 
 
     
     
       14. The method of  claim 13 , wherein a rotation shaft power is controlled to be below a limit. 
     
     
       15. The system according to  claim 1 , wherein a gradual reconfiguration of dual lane logic and the tuning system, based on the probability of sensor faults, accommodates both in-range (hard) sensor failures and out-of-range (soft) sensor failures.